Improved dispersion relations for γγ\to π^0π^0

Abstract

We perform a dispersive theoretical study of the reaction γγ\to pi^0π^0 emphasizing the low energy region. The large source of theoretical uncertainty to calculate the γγ\toπ^0π^0 total cross section for \sqrt{s}\gtrsim 0.5 GeV within the dispersive approach is removed. This is accomplished by taking one more subtraction in the dispersion relations, where the extra subtraction constant is fixed by considering new low energy constraints, one of them further refined by taking into consideration the f_0(980) region. This allows us to make sharper predictions for the cross section for \sqrt{s}\lesssim 0.8 GeV, below the onset of D-wave contributions. In this way, were new more precise data on γγ\toπ^0π^0 available one might then distinguish between different parameterizations of the ππisoscalar S-wave. We also elaborate on the width of the σresonance to γγand provide new values.

10 pages, 5 figures. Extended discussion on the width of the sigma to gamma gamma

References in corpus (2)

• Two-photon decays of hadronic molecules
• Scalar radius of the pion and zeros in the form factor

Cited by in corpus (9)

• Glueball nature of the sigma/f_0(600) from pi-pi and gamma-gamma scatterings
• Amplitude Analysis of High Statistics Results on $\gamma \gamma \to {\pi }^{+}{\pi }^{-}$ and the Two Photon Width of Isoscalar States
• On the radiative decays of light vector and axial-vector mesons
• Two photons into π^0π^0
• The sigma -> gamma gamma Width from Nucleon Electromagnetic Polarizabilities
• On the two-photon decay width of the sigma meson
• Two-photon width and gluonic component of sigma/f_0(600)
• Illuminating hadron structure by scattering light on light
• Scalar radius of the pion and two photons into two pions. Strong S-wave final state interactions